#include <REGX52.H>


void Delay(unsigned int xms);

void main()
{
	unsigned char num = 0x01;
	
	while(1)
	{
		
		P2 = ~num;
		
		if(P3_1 == 0)
		{
			Delay(20);
			while(P3_1 == 0);
			Delay(20);
			
			num = num<<1;
			
			if(num == 0)
			{
				num = 0x01;
			}
		
			
		}
		
		
		if(P3_0 == 0)
		{
			Delay(20);
			while(P3_0 == 0);
			Delay(20);
			
			num = num>>1;
			
			if(num == 0x00)
			{
				num = 0x80;
			}
			
		}
		
		
	}
}


void Delay(unsigned int xms)	//@12.000MHz
{
	unsigned char data i, j;

	while(xms--)
	{
		i = 2;
	j = 239;
	do
	{
		while (--j);
	} while (--i);
	}
	
}

